restart rsync process via shell script

[Mel]

On Monday 29 December 2008 13:35:06 Noah wrote:
> Hi there,
>
> I am trying to figure out the most accurate way to assess if an rsync
> process is running and is established to the remote rsync server and is
> transferring data.  I am writing a bourne shell script to restart rsync
> if the connection to the remote rsync server is lost.
>
> The command "ps ax | grep 'rsync' | grep -v grep"  is not enough because
> the rsync and ssh process can be running but the connection to the
> remote server is no longer ESTABLISHED and the backup is no longer
> proceeding.
>
> Then perhaps the command "netstat -A | grep '192.168.1.10' | grep
> 'ESTABLISHED' | grep -v grep" would be helpful.  But in some cases I
> have found that I have ssh connections to the remote rsync server that
> obfuscate the rsync ssh ESTABLISH statistics.
>
> the rsync command I am using is: "/usr/bin/rsync -avz '/Users/noah/' -e
> 'ssh -p 22' root at 192.168.1.10:/Users"
>
> Any suggestions please?

Set ServerAliveInterval to a low value so the connection is dropped. You can 
do this on the commandline using -e 'ssh -o ServerAliveInterval=10 -p 22'. 
This would drop the connection if the server can't be reached within 10 
seconds.
Once the connection is dropped, rsync should exit with a value other then 0, 
so you can wrap your rsync command in a while loop, like:

KEEP_RUNNING=1
while test ${KEEP_RUNNING} -gt 0; do
	rsync -avz /Users/noah/ -e 'ssh -p 22 -o ServerAliveInterval=10' \
		root at 192.168.1.10:/Users
	KEEP_RUNNING=$?
done

-- 
Mel

Problem with today's modular software: they start with the modules
    and never get to the software part.